Pathogenic Effects Of Asbestos

Our plain-English summary of Pathogenic Effects Of Asbestos, by M. Kannerstein, J. Churg, W.T.E. Mccaughey, et al (1977).

The study

• Authors: M. Kannerstein, J. Churg, W.T.E. Mccaughey, I.J. Selikoff
• Published: Archives Of Pathology And Laboratory Medicine 101(12):623-628, December (1977)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002239. The article is still under copyright, so we describe it here rather than post it.

In plain English

This article was a review, published as a "Special Article," of what was then known about how asbestos causes disease. It did not report a new study of its own. The authors summarized published human population studies, lung tissue examinations, animal experiments and laboratory cell studies. They described the fiber types chrysotile, crocidolite, amosite, anthophyllite and tremolite. They stated that the investigations indicated that all industrially used types cause asbestosis and mesothelioma, except anthophyllite, which had not been linked to mesothelioma in humans. Among the findings they cited: asbestos raised lung carcinoma in smokers by a factor of 8 but only to a limited extent in nonsmokers; mesothelioma was related to asbestos in 20% to 85% of cases across various series; and even minimal exposures resulted in mesothelioma in some individuals. The authors emphasized the physical form and size of fibers, including the ability of fine, short fibers, especially fragmented chrysotile, to reach the pleura. They concluded that much remained to be explained and that researchers disagreed on many findings.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review article ("Special Article") summarizing published human, pathological, animal and in vitro research on the disease-causing effects of asbestos; no new study by the authors
• Who was studied: No study population of its own; the authors reviewed published population studies, tissue studies, animal experiments and cell culture experiments
• Exposure: Asbestos in general: chrysotile (serpentine), and the amphiboles crocidolite, amosite and anthophyllite, plus tremolite (noted in talcum preparations); occupational, indirect, domestic and neighborhood exposure, by inhalation and ingestion
• Main results:
  • The review stated that epidemiologic and experimental investigations indicate all industrially employed fiber types cause asbestosis and mesothelioma, except anthophyllite, which had not been associated with mesothelioma in man although it produced tumors experimentally; all were described as causally related to lung carcinoma
  • Cited finding on smoking: among asbestos workers, asbestos caused only a limited increase in lung carcinoma in nonsmokers but increased the incidence in smokers by a factor of 8; no relationship had been shown between smoking and mesothelioma
  • Cited finding: mesothelioma had been related to asbestos in 20% to 85% of cases in various series
  • Cited study by Pooley: lung tissue in 92% of mesothelioma cases from various countries was positive for fibers by electron microscopy, compared with less than half of control cases
  • The authors wrote that mesothelioma shows less of a dose-response relationship than other asbestos diseases, and that even minimal exposures will result in these tumors in some individuals
  • The review stated that peritoneal mesothelioma appears in general to make up about one fourth of mesothelioma cases
  • The authors wrote that the ability of fine, short fibers, especially fragmented chrysotile, to reach the pleura would appear to account for many features of asbestos-related disease
  • The review stated that peritoneal mesothelioma had not been produced in animal feeding experiments, and neither had carcinoma of the gastrointestinal tract
• The authors' conclusion: The authors concluded that much had been learned about the disease-causing effects of asbestos, but much remained to be explained. They noted a lack of agreement on many findings, and they described the cancer-causing process as appearing to rest essentially on physical factors.
• Limitations the authors state:
  • The authors stated that some aspects of the subject were left out because of space limitations
  • The authors noted a lack of unanimity on many findings, including sharply divergent conclusions

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, Crocidolite, Amosite, Anthophyllite, Tremolite, Mesothelioma, Carcinoma, Pleura.

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